Nephroma helveticum Ach.

Lichenogr. Univ.: 532, 1810.
Distribution: N -TAA (Nascimbene & Caniglia 2000), Lomb, Piem (Morisi & Sereno 1995, Piervittori 2003).
Description: Thallus foliose, heteromerous, crisp, 0.15-0.20 mm thick, forming 3-4(-8) cm wide, regular to irregular rosettes, loosely adnate. Lobes 2-5 mm wide, elongate, with subrotund apices, the margins frequently toothed, the fertile lobes with sharp teeth measuring 0.6-1 x c. 0.1 mm. Upper surface grey-brown to dark brown, smooth, finely pubescent, isidiate-phyllidiate. Isidia at first cylindrical, becoming flattened, 0.1-0.2 mm in diam., mostly marginal but later expanding on the upper surface. Medulla white. Lower surface dark brown to black, paler at margins, pubescent or tomentose, not papillate. Apothecia common, immersed on lower surface at tips of lobes, to 8 mm across, cup-shaped, sessile, with a brown disc, emarginate, the dorsal surface rough and tomentose. Epithecium brownish; hymenium and hypothecium colourless. Asci 8-spored, fissitunicate, the thickened apex with a K/I+ blue ring, Peltigera-type. Ascospores 3-septate, pale brown, subfusiform, thick-walled, most of them 14-18 x 6-7 μm. Pycnidia immersed, punctiform, Conidia rod-shaped, 3-4 x 1-2 µm. Photobiont cyanobacterial (Nostoc). Spot tests: upper cortex K-, C-, KC-, P-; medulla K+ pale yellow or K-, C-, KC-, P-. Chemistry: upper cortex with an unknown brown pigment; medulla with peltidactylin and other terpenoids.
Note: a cool-temperate to southern boreal-montane, circumpolar lichen found on bark, exceptionally on siliceous rocks in humid, but somehow subcontinental upland areas; probably more widespread in the Alps, but never common, and strongly declining. The Italian material should be checked against the very similar N. tropicum, which also occurs in Italy (see Timdal & al. 2021). Earlier records for Venezia Giulia and Toscana refer to N. resupinatum, that from Veneto to N. tropicum. It is included in the Italian red list of epiphytic lichens as “Vulnerable” (Nascimbene & al. 2013c).
Growth form: Foliose, broad lobed
Substrata: bark
Photobiont: cyanobacteria, filamentous (e.g. Nostoc, Scytonema)
Reproductive strategy: mainly asexual, by isidia, or isidia-like structures (e.g. schizidia)

Commonnes-rarity: (info)

Alpine belt: absent
Subalpine belt: extremely rare
Oromediterranean belt: absent
Montane belt: very rare
Submediterranean belt: absent
Padanian area: absent
Humid submediterranean belt: absent
Humid mediterranean belt: absent
Dry mediterranean belt: absent

pH of the substrata:


Solar irradiation:








Altitudinal distribution:


Predictive model
Herbarium samples

Curtis Randall Björk, - CC BY-SA 4.0
British Columbia, Canada, first western range of the Rocky Mountains over the Robson Valley, British Columbia, Canada

P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (27254)

Triin Aimla; Owner: University of Tartu

P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (34253)